What is co-expressed with a TCR?

Compare and contrast an Ig and a TCR

Ig recognize macromolecules and small enzymes, TCR recognize pieces of antigens (peptides) that are presented to them by MHC on APCs; TCR are more diverse than Ig, but each clone for a unique antigen; antigen recognition is mediated by the variable region of heavy and light chains of membrane IG, in TCR recognition is mediated by the variable region of α and β chains

Name 3 cells that are APCs

How are MHC genes inherited and expressed?

Describe the steps that lead up to a CD 8 T cell recognizing a pathogen on an MHC 1

1) virus infects cell, 2) viral proteins synthesized in cytoplasm; 3) peptide fragments of viral proteins are bound by MHC I in the ER; the bound peptide is transported by MHC I to the cell surface where they are recognized by CD8 cells

Where does TCR rearrangement occur?

What is a double negative T cell progenitor?

What is positive selection; where does it occur?

in the cortex of the thymus, immature DN TCR rearranges to become a DP T cells; they are tested for antigen recognition on cortical epithelial cells; the ones that have weak recognition for foreign MHC I and II molecules are allowed to migrate to the medulla and then into general circulation

Draw the structure and understand the functions of T cell receptors

What is an alloantigen?

antigens that vary between members of the same species; they come into play with transplant surgery when the graft tissue is rejected by the host because the host recognizes the MHCs on the grafted tissue as "foreign"

What are the functions of gamma-delta+ T cells?

What do regulatory T cells (Treg's) do?

They regulate the activation of naïve autoreactive CD4 and CD8 cells that have the potential to attack the body's healthy tissue; they help make sure that CD8 and CD4 cells do not accidentally damage healthy tissue during an immune response and that they are decommissioned when the pathogen has been killed